Is it permissible for a woman to observe voluntary fast without her husband's permission?
A woman is not permitted to observe a voluntary fast (nafl) while her husband is present without his permission.
What is the ruling on intramuscular injections? Do they break the fast?
Therapeutic injections administered under the skin or into the muscles do not break the fast, as they do not enter the body cavity (jauf) through an open passage.
However, intravenous (IV) injections that provide nourishment do break the fast because they function like food and drink in effect.
What is the ruling on Zakat al-Fitr?
Zakat al-Fitr is obligatory upon every Muslim for themselves and for those they are financially responsible for, provided they possess wealth that is surplus to their and their family's needs on the night and day of Eid.
Ibn Umar reported: "The Messenger of Allah ﷺ made Zakat al-Fitr obligatory—one sa‘ (measure) of dates or one sa‘ of barley—upon every Muslim, whether slave or free, male or female, young or old." [Narrated by Al-Bukhari]
Its estimated amount is approximately 2,500 grams of wheat or rice, and the General Iftaa` Department issues an annual ruling specifying its monetary value.
Is it permissible for a wife to boycott (not to attend to his different needs) her husband?
It isn`t permissible for the woman to boycott her husband unless he is the reason behind that, and it is recommended that both spouses seek the advice of righteous people to make reconciliation.